The Effect of Oral Probiotics on Oral Hygiene and Halitosis in Orthodontic Patients.

The Effect of Oral Probiotics on Oral Hygiene and Halitosis in Orthodontic Patients: a Randomized Controlled Trial

Brackets, bands, ligatures and wires in patients receiving orthodontic treatment with fixed appliances are areas that trap food and impede oral hygiene. An ecological environment facilitating the growth of microorganisms (Actinobacillus, Bacteroides, Prevotella etc.) emerges in the mouth and may cause caries, enamel white spots, gingival inflammation and halitosis. Despite the use of specialized orthodontic brushes, interdental brushes, mouthwashes and topical fluorides, plaque removal remains inadequate in patients with fixed orthodontic appliances. On the other hand, patients undergoing orthodontic treatment with aligners have been found to have better oral hygiene because of less plaque accumulation in their mouth.

Probiotics are defined as non-pathogenic bacteria that can benefit the host's general health when taken in sufficient amounts through nutrition. Nowadays probiotics can be used to enhance oral health as they are found to reduce dental biofilm formation, prevent and decrease halitosis in children, adolescents and adults. To date, there are few randomized controlled trials (RCTs) examining the efficacy of oral probiotics in patients with fixed orthodontic appliances and none reporting the incidence of halitosis and the effect of probiotics in orthodontic patients wearing aligners.

Study Overview

• Status: Completed
• Conditions: Probiotics; Halitosis; Orthodontic Appliance Complication
• Intervention / Treatment: Dietary supplement: Probiotics; Dietary supplement: Placebo tablet

Detailed Description

The aim of the study is to investigate the effect of the oral probiotic Lactobacillus salivarius on oral hygiene indices and halitosis in patients wearing orthodontic braces and patients wearing orthodontic aligners. The study is a prospective, randomized, placebo-controlled, double blinded, with four parallel groups and an equal allocation ratio in all groups. Patients 12-18 years old undergoing fixed orthodontic treatment will be randomly allocated to probiotic group A (n=30) and placebo group B (n=30). Patients ≥18 years old wearing aligners (Invisalign™ ) will be randomly allocated to probiotic group C (n=30) and placebo group D (n=30). All participants will consume lozenges for one month. Assessments will be taken at baseline, at the end of the intervention and at a 2 month free-intervention follow-up. The outcome measures will be modified plaque index (PI), modified gingival index (GI) and halitosis-causing volatile sulfur compound (VSC) levels. Results will be announced at the end of the study.

• Study Type: Interventional
• Enrollment (Actual): 120
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Greece
  • Attica
    • Athens, Attica, Greece, 11527
      • National and Kapodistrian University of Athens, School of Dentistry, Departments of Orthodontics

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 8 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Patients eligible for the trial must comply with all of the following at randomization:

  • Age between 12 and 18 years for the group with conventional orthodontic appliances This age group represents the majority of patients seeking orthodontic treatment and is homogeneous regarding occupational status (high-school and lyceum students in Greece). Younger patients might present with cooperation problems.

Age ≥18 for the Invisalign™ group This age group represents the majority of patients seeking orthodontic with aligners (Invisalign™) regarding social status and other factors.

• Good general health
• Fixed orthodontic appliances Patients should have fixed labial appliances (brackets) on all teeth from central incisor to first molar, in both the maxillary and the mandibular arch. Fixed appliances should have been placed at least two months before the patient is accepted into the study and remaining treatment should be at least 3 months. All brackets will be the same (metallic, conventional/not self-ligating, same size). Molars should be banded (same bands on all molars) and all other teeth bonded.
• At least 20 natural teeth (in case of extraction orthodontic treatment patients can be enrolled two months after extractions) The outcomes will be evaluated at all teeth from first molar to first molar.

Exclusion Criteria:

• Patients will be excluded for any of the following reasons:

  • Active caries
  • Periodontitis
  • Syndromes, mental disabilities and craniofacial deformities
  • Smoking or use of other tobacco products
  • Dental fluorosis/tooth malformation
  • Antibiotics during the last 2 months
  • chlorhexidine in the previous 3 week
  • Suffering from any disease within 2 months before measurements
  • Allergy to dairy products
  • Participation in other trials Consent / assent Parents/guardians and patients will provide written informed consent and patients will provide written assent before randomization and before any procedures are applied.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental group 1: patients, age 12-18, conventional brackets, Oral probiotics lozenges; 30 patients, age 12-18,with conventional brackets,will get Oral probiotics lozenges	Dietary supplement: Probiotics; In our study oral probiotics Lactobacillus salivarius Oral S1 11 (Prodilac Oral, Frezyderm) will be tested in two Experimental groups
Experimental: Experimental group 2: patients, age ≥18, Invisalign™ appliances, Oral probiotics lozenges; 30 patients, age ≥18, Invisalign™ appliances,wil get Oral probiotics lozenges	Dietary supplement: Probiotics; In our study oral probiotics Lactobacillus salivarius Oral S1 11 (Prodilac Oral, Frezyderm) will be tested in two Experimental groups
Placebo Comparator: Control group 1: patients, age 12-18, conventional brackets, placebo lozenges; 30 patients, age 12-18, conventional brackets,will get placebo lozenges	Dietary supplement: Placebo tablet; In order to avoid possible bias, probiotics will be compared with placebo lozenges/no probiotic in two Control groups
Placebo Comparator: Control group 2: patients, age ≥18, Invisalign™ appliances, placebo lozenges; 30 patients, age ≥18, Invisalign™ appliances,will get placebo lozenges	Dietary supplement: Placebo tablet; In order to avoid possible bias, probiotics will be compared with placebo lozenges/no probiotic in two Control groups

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Silness and Löe plaque index (PI-M)	The Silness and Löe index does not take into account the pattern of plaque accumulation in orthodontic patients. To overcome this problem, divided the tooth into mesial, distal, gingival, and incisal regions in relation to the bracket and scored plaque in each region using the four codes of the original index (0 to 3). The values are summed to obtain a total score, which ranges from 0 to 12 for each tooth. This modified index is recommended for patients with fixed orthodontic appliances because it acknowledges the usual effects of orthodontic appliances on plaque distribution and has much greater categorical discrimination.	baseline-1 month
Modified Silness and Löe plaque index (PI-M)	The Silness and Löe index does not take into account the pattern of plaque accumulation in orthodontic patients. To overcome this problem, divided the tooth into mesial, distal, gingival, and incisal regions in relation to the bracket and scored plaque in each region using the four codes of the original index (0 to 3). The values are summed to obtain a total score, which ranges from 0 to 12 for each tooth. This modified index is recommended for patients with fixed orthodontic appliances because it acknowledges the usual effects of orthodontic appliances on plaque distribution and has much greater categorical discrimination.	1 month- 3 month
Modified Gingival index (GI-M)	The Gingival Index (GI) is a measure of the severity of gingivitis and is scored by measuring the amount of gingival inflammation, also considering redness and bleeding .	baseline-1 month
Modified Gingival index (GI-M)	The Gingival Index (GI) is a measure of the severity of gingivitis and is scored by measuring the amount of gingival inflammation, also considering redness and bleeding.	1 month- 3 month
Halitosis/ VSCs levels	VSCs levels will recorded at each time point with the use of OralChromaTM. OralChromaTM is a portable gas chromatograph, which uses ambient air as a carrier gas and a semiconductor (In2O3) gas sensor to detect volatile sulphur compounds (VSCs), i.e. the concentrations of H2S, CH3SH and (CH3)2S.	baseline-1 month
Halitosis/ VSCs levels	VSCs levels will recorded at each time point with the use of OralChromaTM. OralChromaTM is a portable gas chromatograph, which uses ambient air as a carrier gas and a semiconductor (In2O3) gas sensor to detect volatile sulphur compounds (VSCs), i.e. the concentrations of H2S, CH3SH and (CH3)2S.	1 month- 3 month

Collaborators and Investigators

• Sponsor: University of Athens
• Collaborators: Align Technology, Inc.
• Investigators: Principal Investigator: Iosif Sifakakis, Associate Professor, University of Athens

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2022
• Primary Completion (Actual): November 20, 2025
• Study Completion (Actual): November 20, 2025

Study Registration Dates

• First Submitted: December 2, 2022
• First Submitted That Met QC Criteria: December 12, 2022
• First Posted (Actual): December 15, 2022

Study Record Updates

• Last Update Posted (Actual): December 10, 2025
• Last Update Submitted That Met QC Criteria: December 3, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Probiotics; Halitosis; Aligners; Fixed Appliances
• Additional Relevant MeSH Terms: Signs and Symptoms, Digestive; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Halitosis; Dietary Supplements; Food; Diet, Food, and Nutrition; Physiological Phenomena; Food and Beverages; Probiotics
• Other Study ID Numbers: 444/27.07.2020

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No